package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.hmdp.dto.Result;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.FollowMapper;
import com.hmdp.service.IFollowService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IUserService;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class FollowServiceImpl extends ServiceImpl<FollowMapper, Follow> implements IFollowService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private IUserService userService;

    private static final String FOLLOW_PREFIX = "follow:";


    @Override
    public Result followUser(Long followedId, Boolean isFollow) {
        Long userId = UserHolder.getUser().getId();
        String redisKey = FOLLOW_PREFIX+userId;
        if(isFollow){
            //当前用户要关注该用户，在表中添加记录
            Follow follow = new Follow();
            follow.setUserId(userId);
            follow.setFollowUserId(followedId);
            boolean isSuccess = save(follow);
            //插入数据库成功，在redis中加入对应数据
            if(isSuccess){
                stringRedisTemplate.opsForSet().add(redisKey, followedId.toString());
            }

        }else {
            //当前用户要取关，删除表中对饮的记录
            boolean isSuccess = remove(new QueryWrapper<Follow>()
                    .eq("user_id", userId)
                    .eq("follow_user_id", followedId));
            if(isSuccess){
                stringRedisTemplate.opsForSet().remove(redisKey, followedId.toString());
            }
        }

        return Result.ok();
    }

    @Override
    public Result isFollow(Long followedId) {

        Long userId = UserHolder.getUser().getId();

        //检查表中是否有记录
        Integer count = query().eq("user_id", userId)
                .eq("follow_user_id", followedId)
                .count();
        return Result.ok(count>0);
    }

    @Override
    public Result commonFollow(Long current) {
        String currentKey = FOLLOW_PREFIX+current.toString();
        String userKey = FOLLOW_PREFIX+UserHolder.getUser().getId().toString();
        Set<String> commonFollowIdStr = stringRedisTemplate.opsForSet().intersect(userKey, currentKey);
        if(commonFollowIdStr==null || commonFollowIdStr.isEmpty()){
            return Result.ok(Collections.emptyList());
        }

        List<Long> ids = commonFollowIdStr.stream().map(Long::valueOf).collect(Collectors.toList());
        List<UserDTO> userDTOS = userService.listByIds(ids).stream().map(user -> BeanUtil.copyProperties(user, UserDTO.class)).collect(Collectors.toList());

        return Result.ok(userDTOS);
    }
}
